1. Field of the Invention
The present invention relates to an image taking apparatus which includes an image pickup device and which forms a subject image on the image pickup device and produces a picture signal.
2. Description of the Related Art
Many image taking apparatuses include light-emitting sections which emit flash toward a subject in synchronization with image taking action. In such an image taking apparatus, if luminous intensity distribution of flash emitted from the light-emitting section is set to a wide-angle side, much light is emitted out of image taking angle of view corresponding to a telephoto angle in response to a zoom switch being operated to a telephoto side and therefore, electric power is consumed in vain. Therefore, many image taking apparatuses employ a technique in which luminous intensity distribution of flash can be changed in association with operation of the zoom switch (see Japanese Patent Application Laid-open (JP-A) No. 55-129326 for example). According to JP-A 55-129326, at least one of an arc tube and a reflector is moved forward or rearward in the optical axial direction so that luminous intensity distribution suitable for the image taking angle of view is obtained in accordance with operation of the zoom switch.
However, since the arc tube such as a xenon tube is of rod-like shape, there still remains a problem that redundant light is emitted toward side of the arc tube and electric power is consumed in vain.
As described in Japanese Patent Application Laid-open No. 2-291538, there is a technique in which side reflection means is provided on a side of the arc tube, wastefully discharged electric power is emitted into the image taking angle of view, thereby enhancing the electric power efficiency.
As a technique in which the luminous intensity distributions is adjusted to enhance the electric power efficiency, there is a technique in which Fresnel lens is moved forward and rearward in the optical axial direction in addition to the arc tube or the reflector, thereby bringing flash into preferable luminous intensity distribution (see Japanese Patent No. 3262779), and there is also a technique in which a reflector plate is deformed to bring flash into preferable luminous intensity distribution (see Japanese Patent Application Laid-open No. 6-180469).
In any of the techniques disclosed in the patent documents 1 to 4, however, there is a problem that since a mechanism which moves the arc tube or the reflector in the optical axial direction, a mechanism which moves the Fresnel lens forward and rearward, or a mechanism which deforms the reflector must be provided, the structure of the light-emitting section becomes complicated and is increased in size.